Accumulator counterbalanced three chamber cylinder for artificial lift operations

Abstract

An artificial lift system for use with a subterranean well can include a cylinder having a piston reciprocably disposed therein, the piston having opposing sides, one side being selectively communicable with at least one accumulator, and the other side having two areas, each of the areas being selectively communicable with a hydraulic pressure source and a hydraulic reservoir, and a gas pressure source connected to the accumulator, the gas pressure source including a gas compressor connected between at least one gas container and the accumulator. A method of controlling an artificial lift system can include connecting a cylinder to a hydraulic pressure source and to at least one accumulator, the accumulator being connected to a gas pressure source, and operating a gas compressor of the gas pressure source, thereby increasing hydraulic pressure applied to the cylinder from the accumulator.

What is claimed is: 
     
       1. An artificial lift system for use with a subterranean well, the system comprising:
 a cylinder having a piston reciprocably disposed therein, the piston having first and second opposing sides, the first side having discrete first and second areas, each of the first and second areas being selectively communicable with a hydraulic pressure source and a hydraulic reservoir, and the second side being selectively communicable with at least one accumulator; and 
 a gas pressure source connected to the accumulator, the gas pressure source including a gas compressor connected between at least one first gas container and the accumulator. 
 
     
     
       2. The system of  claim 1 , wherein the gas pressure source further comprises at least one second gas container connected to a discharge side of the gas compressor. 
     
     
       3. The system of  claim 2 , wherein the second gas container is connected to the accumulator. 
     
     
       4. The system of  claim 2 , wherein the at least one second gas container comprises multiple second gas containers. 
     
     
       5. The system of  claim 1 , wherein the accumulator comprises a bladder. 
     
     
       6. The system of  claim 5 , wherein the bladder is exposed on one side to the gas pressure source, and on an opposite side the bladder is selectively communicable with the second side of the piston. 
     
     
       7. The system of  claim 1 , wherein the at least one accumulator comprises multiple accumulators. 
     
     
       8. A method of controlling an artificial lift system, the method comprising:
 connecting a cylinder to a hydraulic pressure source and to at least one accumulator, the accumulator being connected to a gas pressure source, wherein the cylinder has a piston reciprocably disposed therein, the piston having first and second opposing sides, the first side having discrete first and second areas, each of the first and second areas being selectively communicable with the hydraulic pressure source and a hydraulic reservoir, and the second side being selectively communicable with the accumulator; and 
 operating a gas compressor of the gas pressure source, thereby increasing hydraulic pressure applied to the cylinder from the accumulator. 
 
     
     
       9. The method of  claim 8 , further comprising connecting at least one gas container to a discharge side of the gas compressor. 
     
     
       10. The method of  claim 9 , further comprising connecting the gas container to the accumulator. 
     
     
       11. The method of  claim 9 , wherein the at least one gas container comprises multiple gas containers. 
     
     
       12. The method of  claim 8 , wherein the accumulator comprises a bladder. 
     
     
       13. The method of  claim 12 , wherein the bladder is exposed on one side to the gas pressure source, and on an opposite side the bladder is selectively communicable with the cylinder. 
     
     
       14. The method of  claim 8 , wherein the at least one accumulator comprises multiple accumulators. 
     
     
       15. A well system, comprising:
 a downhole pump actuated by reciprocation of a rod; 
 a cylinder that reciprocates the rod in response to pressure applied to the cylinder, the cylinder having a piston reciprocably disposed therein, the piston having opposing first and second sides, the first side having discrete first and second areas; 
 at least one accumulator that applies pressure to the second side of the piston; 
 a hydraulic pressure source that applies pressure to the first side of the piston; and 
 a gas compressor that increases gas pressure applied to the accumulator. 
 
     
     
       16. The system of  claim 15 , further comprising at least one gas container connected to a discharge side of the gas compressor. 
     
     
       17. The system of  claim 16 , wherein the at least one gas container comprises multiple gas containers. 
     
     
       18. The system of  claim 15 , wherein the accumulator comprises a bladder. 
     
     
       19. The system of  claim 15 , wherein the at least one accumulator comprises multiple accumulators.